1. Field of the Invention
The present invention relates to a touch screen input scheme. More particularly, the present invention relates to an apparatus and method for processing a touch screen input using an electronic pen such as a stylus pen.
2. Description of the Related Art
Recent display devices have widely employed a touch screen input scheme in which a user directly touches a screen using a finger or an electronic pen to perform inputs. Such a touch screen input scheme has been mainly employed in a portable terminal such as a smart phone, a portable phone, a notebook computer, an all-in-one Personal Computer (PC), a tablet PC, a Portable Multimedia Player (PMP), and the like. The touch screen input scheme is an input device which allows a user to touch a certain portion of a display screen to input information instructed by the user, and provides an intuitive and convenient user interface. In particular, a touch input scheme using a pen is effective for designation of precision coordinate input rather than a touch input using a finger. Therefore, the touch input scheme using a pen is suitable to perform graphic functions using a CAD program.
The touch screen input scheme is referred to as a digitizer or an Electric Graphic Input Panel (EGIP), which is generally classified into a resistive scheme, a capacitive scheme, an Electro Magnetic Resonance (EMR) scheme (or an electromagnetic scheme), and the like, according to a method of detecting a position instructed by a user.
The resistive scheme senses a position pushed by a touch using a change of electric current based on a direct voltage that is applied to a touch screen. The resistive scheme senses a contact of a finger or an electronic pen such as a stylus pen when the finger or the electronic pen comes in contact with and applies a pressure to two thin conduction layers of the touch screen.
The capacitive scheme senses an input using capacitive coupling in a state that an alternative voltage is applied to a touch screen, in which a sensed object must be a conductor and more than a predetermined area must vary for the capacitance to be sensed.
On the other hand, the EMR scheme uses a digitizer sensor substrate in which loop coils are arranged. Accordingly, when a user moves an electronic pen, the electronic pen is operated by alternative signals to generate a magnetic resonance, which induces signals in coils of the digitizer sensor substrate. A touch screen can detect a position of the electronic pen through the signals induced in the coils.
According to the EMR scheme, since the position of the electronic pen is identified by sensing an electrical change caused by the contact of the pen with the digitizer sensor substrate having a plurality of coils mounted thereon, it is unnecessary to arrange the sensor substrate on a front surface of a display module, which is different way from the resistive scheme noted above. Accordingly, it is possible to arrange the sensor substrate on a rear surface of the display module. On the other hand, a multiple input device including a digitizer input device employing the EMR scheme and a touch input device capable of sensing a contact of a user's finger can be provided to portable terminals.
Korean Patent Publication No. 10-2012-0079595, entitled to the present applicant on Jul. 13, 2012, discloses an apparatus and method for correcting an input error of an input device, in which a technique of a touch screen input scheme is described.
On the other hand, a technique which is able to distinguish between a direct contact state of an electronic pen and a non-contact state of the electronic pen, i.e. a hovering state for a touch screen is recently provided. However, a more effective input process is required.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.